Every quarter we get a peek at what some of the biggest investors in the world have been up to for the last three months. This past week, regulatory filings (13-F's) for Q3 gave us the most recent peek into what hedge funds and investors like Warren Buffet think are the hot stocks.

So what did we learn this week?

Famously anti-tech, Warren Buffet took a 5.5% stake in IBM saying he was impressed with where they were taking the company (as an aside, in a CNBC interview he also spoke positively about Microsoft however has a moratorium in investing in the name because of his close friendship with Bill Gates).

Phillip Laffont's Coatue Hedge Fund started a position in Research in Motion as did Leon Cooperman's Omega Advisors, each buying about 1.5 million shares betting on a management shakeup and favourable sales from the upcoming BNX operating system devices.

Laffont and TPG-Axion Capital took a less bullish view on the telecom industry with the former cutting its stake in Qualcomm in half and the latter unloading all of its 37 million share position in Sprint Nextel.

David Tepper of Appaloosa ended its investment in Bank of America and sold off some of its position in Citigroup. Bank names were not completely hated however as many funds took positions in JP Morgan and Morgan Stanley in the last Q. Blackrock and US bancorp were also added to.

Noted investor David Einhorn liquidated his entire Pfizer position as did Tepper.

Last but not least investors were mixed on Green Mountain and Netflix as these market darlings hit some rough patches and had notable investors like Einhorn publically betting against Green Mountain.